An example of the type of thing I hope to do on the machine: We built recessed frame cupboards, and needed an authentic English edge beading on it. Those familiar with the style will know it's a tall order. Pictured below is one of the joints, how it came out, and how it was done...

Hennie: I'm not really rigged to do cupboards anymore, but I used to be in the bussiness. I built that kitchen for the guy who let me use his facilities and steel to build the machine frame. Manually cutting joints was a pain. Having a CNC machine would've saved me a LOT of time...

Hennie: I'm sure it'll pick up again. We also do granite; directly after the world cup, everything just came to a dead halt and it's only starting to pick up again now - hopefully your neck of the woods will follow soon.

I am sure most guys don't find this part to be too difficult; but given the length of our rails, there are a couple of hidden issues. There probably are easier ways, but this is how we did it:

As suggested somewhere on the forums, we built a “trolley” with a laser mounted on top, pointing at a white surface 10 meters away from the machine. The trolley's wheel centres are identical to the bolt spacing on the rails. We then record the position of the laser on the white surface for every space between the bolts.

Knowing the position of the first bolt, and the dot on the white surface, we can draw a corresponding line in CAD. The combination of these lines, gives us an accurate map of the rails' shape. It turns out that, despite my best efforts, the rails had a maximum deviation of 4.68mm - well within shimming distance though.

A nice way of mapping the laser's position, was setting up a camera in front of it on a tripod, and taking pictures of each position. I then superimposed the images over each other, and measured the distances from there - very accurate. From the CAD drawing, shimming sizes were simply measured and transferred to the machine.

It seems to have worked well, and this is the current state of affairs.

Next a strip of granite and an accurate level (used for wheel alignment) will be placed between the rails to level the second rail at the two ends, giving us a new datum to work from on that rail. Wash, rinse, repeat...

The first rail's horizontal straightness is set up conventionally with line and a magnifying glass, the second with a spacer, and finally the gantry's wheels and the magnifying glass.
In theory, the rails should be good by then...